EFFECT OF A CHANGE IN THE STRUCTURAL PARAMETERS
OF PITCH COKE DURING HEAT TREATMENT ON ITS INTERACTION
WITH A SILICON MELT
I. A. Bubenkov,
Yu. I. Koshelev,
A. A. Shvetsov,
N. G. Bardin,
N. A. Makarov,
and A. V. Nasibulin
Translated from Novye Ogneupory, No. 12, pp. 20 – 25, December, 2016.
Original article submitted April 5, 2016.
This article examines the effect of the structural parameters of isotropic and anisotropic pitch cokes that
change with an increase in graphitization temperature on these cokes’ reactivity in relation to a silicon melt.
The graphitization temperature at which the siliconized material is completely impregnated and contains the
maximum amount of silicon carbide is determined for both cokes.
Keywords: microstrain coefficient, degree of graphitization, coherent scattering region, prismatic and basal
Siliconized graphites and siliconized carbon-carbon
composites can be made by having the carbonaceous mate-
rial that is used for siliconizing be graphite obtained by the
high-temperature treatment (graphitization) of isotropic and
anisotropic pitch cokes. From a technological standpoint, it
is important to choose the pitch-coke graphitization tempera
ture that is optimum for ensuring that the lattice parameters
are such as to in turn optimize the ratio of the rate at which
the silicon melt spreads over the surface of the carbonaceous
material to the rate of the reaction between them. An analysis
of the literature data [1 – 3] has shown that reducing the
number of defects in the crystalline structure of the carbon
filler increases its reactivity in relation to silicon and im
proves the spreading of the silicon melt over its surface.
On the other hand, carbonaceous materials with an unor
dered structure are also highly reactive in relation to silicon
but are less amenable to spreading. This can lead to rapid ob
struction of the capillaries and does not always ensure good
The goal of our investigation was to examine how the
structural parameters of carbonaceous materials that change
during high-temperature treatment affect their reactivity in
relation to silicon melts.
MATERIALS AND METHODS USED IN THE STUDY
The objects chosen for study were isotropic and
anisotropic pitch cokes with different point ratings for micro
structure and different heat-treatment temperatures ranging
from 1200 to 2800°C in 200°C increments. After the high-
temperature treatment was administered and the x-ray struc
tural parameters were determined on a DRON-4 diffracto
meter, we siliconized specimens of the test cokes by the “irri
gation” method. This method entails spraying the surface of
the carbonaceous semifinished product with a silicon melt
through pores in a crucible at temperatures above 1800°C.
The degree of defectiveness of the siliconized specimens was
determined by x-ray flaw detection with high-energy radia
tion. This made it possible to identify regions that had not
been impregnated with silicon, as well as to find evidence of
cracking and delamination. The phase composition of the
specimens after siliconizing was determined by the gravi
Refractories and Industrial Ceramics Vol. 57, No. 6, March, 2017
1083-4877/17/05706-0631 © 2017 Springer Science+Business Media New York
Scientific-Research Institute of Graphite-Based Structural Mate
rials “NIIgrafit,” Moscow, Russia.
Russian University of Chemical Engineering im. D. I. Mende
leeva, Moscow, Russia.